Hydraulic remote control system



Nov. 27, 1945. 1.. E. DOUGHERTY HYDRAULIC REMOTE CONTROL SYSTEM Filed Sept. 21, 1942 2 Sheets-Sheet l Q I main Patented Nov. 27, ,1945

a v A UNITED STATES PATENT OFFICE 2,389,963 nrnaamo REMOTE con'rnor. SYSTEM Lemuel E. Douglierty, Miami, Fla.

Application September 21, 1942, Serial No. 459,176

' 7 Claims. (o1. Gil-54.5)

This invention relates to an improved hydraulic remote control of the type wherein a single tube is used as connection between the controlling station, usually called the transmitter, and the controlled station, usually called the receiver.

One such system is shown in my copending application Serial No. 449,942, flied July 6, 1942.

In my aiorementioned copending application is shown a locking means for control systems of this type which consists of a valve apparatus located in the system between the transmitter and receiver which normally preventspassage of fluid between the transmitter and receiver thus locking the control system against unauthorized movement. This fluid locking means effectively holds the control from movement due to vibration or any external force applied at the cylinder when the pressure in chamber 22 isreceiver, but in installations where the receiver is subject to large variations in temperature the resultant expansion or contraction of the hydraulic fluid in the receiver cylinder causes some will be apparent during the course of the followa ing detailed description.

Inthe accompanying drawings oi apparatus illustrative of this invention,

Figure 1 is an assembly view, with parts sectioned vertically, of the control equipment.

Figure 2 is a crosssectional view taken sub-' stantially on its respective line shown in Figure 1.

Figure 3 is an enlarged cross sectional view taken substantially on its respective line shown in Figure 1.

Figure 4 is an enlarged vertical section of a portion of the receiver showing a modified form of that shown in Figure 1.

Figure 5 is a cross sectional view taken substantially on its respective line shown in Figure 4. Referring to Figure l, the letter A designates the transmitter assemblage and the letter B the receiver assemblage which are connected together by the fluid conduit or tube 35. The transmitter assemblage A comprises a supporting frame l0 upon which is mounted a cylinder H. A fluid actuating piston I2 is siidable in the cylinder.

This piston is relatively long and includes the piston head 13 having minute transverse openings i4 therein. The upper end 20 of the piston is provided with the seal I6 to prevent leakage of fluid past this end of the piston thus forming a fluid chamber 22 in the cylinder between the heads of the piston. The lower, head it of the piston is provided with a yieldable sealing cup [5 of a nature which will prevent flow or fluid upwardly but will permit fluid to pass through the openings it into the lower chamber 23 of the greater than exists in chamber 23.

Fluid from a supply tank flows by gravity or other means through the tube It and connecting fitting 9 into the chamber 22 through the inlet port I'i. As the .distance between the heads of the piston i2 is equal to its travel in the cylinder,

it is apparent that the port i1 is open at all times and the chamber 22 always fllled with fluid at not less than atmospheric pressure. The compensating port I8 is provided to permit fluid in the pressure part of the system, when there is an excess thereof, to return to the supply tank at the most upward movement of the piston when this port I8 is uncovered, as will be subsequently referred to.

The operating handle 29 is integral with the lever 26 which is pivoted at 28 upon the frame Ill. The connecting rod 24 has a pivot connection to the lever at 25 and at its other end is pivoted at 2| to the upper end 20 of the piston i2, A spring supporting rod 30 is pivoted at 21 to the lever 26 and is slidably supported within a collar 3i. The latter is trunnioned in the frame. it) by the pivot bolts 38 and 39 as shown in Figure 2 of the drawings. A spring 33, under compression, is supported upon the rod 30, being seated at one end in the collar 3i and. at its other end being heldin compressed relation upon the rod by means of a retaining disc 34 held on the rod in adjustable relation by means of a nut 35. It is of course apparent that the compression force of the spring acts through the linkage to maintain the fluid in the chamber 23 in the lower part of cylinder ll under pressure. Movement of the handle 29 and lever 26 increases or decreases the compression of the spring 33, but the leverage and linkage connecting this spring with the piston is so arranged, as set forth in my aforementioned copending application, that it exerts a substantially constant pressure force upon the fluid in the cylinder regardless of the position of the piston therein throughout its range of travel. Stop shoulders 31 and 32 are provided upon the at 41 to the connecting rod 45 which .fluid, downward movement piston l2 travel than the piston of the receiver, to be subsequently described, so that the compensatin port l8 can be uncovered if required.

Referring to the receiver B, the same is in many respects similar. to the transmitter assemblage. It is provided with a frame 40 which supports the cylinder 4| having a piston 42 slid able therein. This piston is provided with a sealing cup 43. A lever 43 is pivoted "at 49 to the frame 40 and at its other end pivotally connected has pivotal connection at 44 with the piston 42. An angular extension of the lever is. provided with'the openings 5 for the connection of control rods,-

etc., in a manner well understood by those skilled in the art to which this invention relates. The

details of the spring assemblage are substantially the same as that of the transmitter. The spring supporting rod 52 is pivoted at 48 to the lever 46 and is slidably supported in the collar which is trunnioned in the frame 40 similar to the collar 3| in frame It), as shown in Figure 2. A spring 51 is seated at one end'in collar SI and held under compression by means of a retaming disc 54 held upon the rod by a nut 55. Stop shoulders 56 and 53 upon the rod 52, limit the travel ofthe piston collar 5|. v

The locking apparatus associated with-the receiver assemblage is contained in the casing 60 which is attached to the end of the cylinder 4|.

A chamber 64 is provided in the central part of the casing, through which extends the rod 62 which is rigidly attached to the piston 42. Fluid connection from the receiver cylinder to the transmitter cylinder is accomplished by means of the chamber 64 and passage 65 in the casing 80, the connecting fitting GI and the tube 36. An extension 63 is provided for the casing 60 to accommodate the rod 62 in downward movement of the piston.

Referring to the assemblages A and B as shown in Figure 1, it is apparent that with the system fllled with the proper quantity of a hydraulic of the transmitter will cause a corresponding upward movement of the receiver piston 42. After such movement has taken place an upward movement of the transmitter piston will cause corresponding downward movement of the receiver piston 42 by action of the spring 51. As the springs of transmitter and receiver exert a substantially equal constant pressure force upon the fluid in the system, regardless of the positions of their respective pistons in the cylinders, it is a substantially balanced its own part to assume a position other than where moved. Insomepositions there may be a slight unbalance of forces between the springs of transmitter and receiver, but the locking apparatus, to be subsequently described, prevents any undesired movement.

Compensatiom for loss, expansion or contraction of the hydraulic fluid is accomplished by movement of the transmitter piston l2 to its upmost position, with the stop 32 against the collar 3|, at which point the compensating port It is uncovered and'is open into the pressure chamber 23 in the cylinder ll below the piston seal-- 42 by seating against the est position with the stop 56 against the collar GI and the excess fluid will escape through the compensatin p rt [8 into the supply tank. If there is a deficiency of fluid in the system, the receiver piston 42 will reach its lowest position before the transmitter piston l2 has reached its corresponding upper position. In this case, further upward movement of the transmitter piston, by exertion of force on the handle 23, will cause the fluid pressure in the chamber 23 to fall below that in chamber 22 which is connected to the supply tank. Therefore fluid will pass through the openings l4, around the sealing cup 15 and into the chamber 23, thus re-establishing the proper quantity in the system. In either case of an excess Ordeflcieny of fluid in the system, if the operating handle 29 is moved until the stop 32 strikes the collar 3|, and then released, the transmitter piston will return to its normal position closing the compensating port l8 from the pressure chamber 23, through the action of the spring 33, and the pistonswill be re-established in proper relation.

Referring to Figure 3, the fluid chambers 15 and 16 are provided in opposite sides of the casing 80. The flexible diaphragms 83 and 84- are supported in these chambers 15 and 16 respectively. The spring 11 is held under compression upon the diaphragm 83 by means of the cap I9 the fluid pressure acting wardly and a greater force acting to move rod 18 ing cup 15. If there is an excess of fluid in the system, downward movement of the receiver piston 42 will continue until it has reached its lowten; is present upon phragms at all times.

diaphragm 83, with the shoulder 12 which is adjustable in the spring barrel 18. The spring is similarly held,under compression upon the diaphragm 44 by the cap 82 which is adjustable in the spring barrel ll. The passages 68 connect the chambers 15 and 16 with the chamber 84 so that the fluid pressure in the systhe inward sides of the dia- The rod II is slidably in the casing and attached to the provided to the casing and limit its outward supported seat against movement. The rod the casing and attached to the diaphragm 84, with the shoulder 14 provided to limit its outward movement. The fixed locking member 68 is rigidly attached to the casing and supports the pin 10 on which the hinged locking member 89 is pivotally mounted. The inward sides of the formed to accommodate the rod 62 which passes between them and is attached to the piston 42, as shown in Figure 1; It is apparent that force exerted by the rod ll against the hinged locking member 69 will tend to clamp the rod between the locking members and there will be a high frictional resistance against its movement.

In considering'the forces actuating the locking be noted that the fluid exposed area of diaphragm 84 i greater than that of the diaphragm l3. and the spring 80 heavier than the spring 11. The normally constant fluid pressure in the system exerts a force outwardly upon the diaphragms proportionate to their respective areas, so there is normally a force from to move rod ll outoutwardly. The spring 11 exerts a greater force than the normal fluid pressure acting upon the diaphragm 83, so there is a resultant inward force onred II which acts upon the hinged locking member 89, thus clamping the rod 62. The spring 80 exerts a force slightly less than the force of the fluid pressure acting upon diaphragm 84 so there is normally a-slight resultant force acting outwardly onrod 13 so the shoulder 14 rests against the casing; It is apparent that the 13 is slidably supported in locking apparatus.

2,889,983 3 forces from the springs 11 and 80, acting throughv the rods 'II and 13 respectively, act in opposite relation upon the locking member 69; but the area of diaphragm 04 is such that the normal fluid pressure acting upon it will hold rod 13 with its shoulder 14 against the casing, in the position shown in Figure 3, so it will have no effect upon the locking member.

When the operator desires to move the control he exerts force on the operating handle 29 with a resultant increase or decrease in the fluid pressure in the system. It the transmitter piston is moved downwardly, so that the fluid pressure increases a predetermined amount the force of the fluid pressure upon diaphragm 83 will be greater rod 13 will move inwardly and rest against the locking member 69. As the spring 80 is stronger than the spring 11, this decrease in fluid pressure allows the spring 80 to overcome the force exerted upon the locking member 69 by the spring 11, thus relieving the clamping pressure on the rod 62 and the receiver piston 42 will be free to move.

It is thus seen that under the normal fluid pressure in the system, as determined by the spring means of the transmitter, the receiver piston will be held against movement by the clamping action oi the locking member through force exerted by the spring 'I'I, but that a predetermined increase or decrease in fluid pressure, caused by the operators exertion of force upon supported in 'the casing with the shoulder I23 limiting its outward travel; The rocking member I20 is pivoted to the casing at I2I and pivotally connected at II9 to the rod III. The latter is slidable in the casing and attached to the diaphragm I06 with the shoulder II8 limiting its travel. The locking members 99 and I00 are pivotally mountedupon the pin I0 I, which is supported bythe flanges 08 shown in Figure 4. The passages II 5 and H6 connect the chambers I I 4 and H3 with the chamber 93 so that fluid pressure from the transmitter is present on the inner sides of diaphragms I05 and I06.

In this form of construction, unlike that shown in Figure 3, the diaphragms may be of equal size, if desired. In that case the spring I00 is stronger than the spring II2. Force of the spring I09 is greater than the force from the normal fluid pressure upon the diaphragm I00, so there is a resultant force exerted inwardly by the rod I22 upon the lockingmember 08. Force of the spring I I2 is less than the force from the normal fluid pressure upon diaphragm I08, so there is a resultant force transmitted through the rocking member I20 inwardly upon the locking member I00. Under normal fluid pressure these two forces acting upon opposite sides of the locking members are substantially equal and the locking members assume a position as shown in Figure 5 and clamp the rod 98 against movement.

the transmitter operating handle, removes the I pressure upon the locking member and allows free movement of the receiver piston. As the receiver piston is normally held against movement. any expansion, contraction or leakage of th hydraulic fluid in the system will cause movement only in the transmitter; and the control system is held against movements due to external forces such as vibration,

In Figures 4 and 5 is shown a modifled form of Referring to Figure 4, there is shown a, portion of the receiver cylinder 4| with the piston ,90 equipped with the sealing cup 9| slidable therein. The rod 96 is attached to the piston by means of a ball and socket connection. It thus has a limited swivel action. The casing 02 is attached to the end of cylinder I and contain the chamber 93 in which the looking members are located. The locking member I00 is pivotally mounted between the flanges 98 which extend into the chamber 93. An extension 91 is provided on the casing to accommodate the rod 90. Fluidconnection from the transmitter cylinder is by means of the tube 38, the connecting fltting 94 and the passageway 95, so that fluid pressure from the transmitter is present at all times in the chamber 03 and in the receiver cylinder.

Reierring to Figure 5, the flexible diaphragms I05 and I06 are mounted in the fluid chambers Ill and I I3 in opposite sides of the casing 92.

the diaphragm I05 by means of the cap I08 which is adjustable in the spring barrel I01, The spring H2 is held under compression upon the diaphragm I08 by means of the cap III which is adjustable in the spring barrel 0. The rod I22 is attached to the diaphragm I05 and slidably leasing the pressure on looking member 99, until the shoulder I23 on rod. I22 strikes the casing. At this point no force is exerted on the locking member 80, so there is no clamping action on rod Stand the receiver piston is free to move. A decrease'trom the normal fluid pressure upon the diaphragms will cause them to move inwardly due to theforce exerted by their springs. Inward movement of diaphragm I05 causes an in- 'ward movement of the locking member 99 until it strikes the stop I24. Inward movement of diaphragm I06 allows an outward movement of the locking member I00 which releases the clamping pressure on the rod 96 and allows movement of the receiver piston. a

While for purposes of illustration in the drawings considerable clearance is shown between the stops and other parts of the locking apparatus, in I practice the parts may be fitted closely together The spring I00 is held under compression upon and only very slight movements of the diaphragms will be required to impose Or release the force upon the locking members.

Various changes in the shape, size, arrangement of parts and details of construction may be made to the forms of the invention herein shown, without'departing from the spirit oi. the invention Or the scope of the claims.

I claim:

1. In a hydraulic remote control system having a receiver assemblage with a movable element, 9. locking device comprising clamping means adapted to oiIer frictional resistance to movements or the movable element in the reovercoming of the force from said first named spring means upon predetermined decrease in fluid pressure from the normal fluid pressure in the system.

2. In a hydraulic remote control system having a receiver assemblage with a, movable element, a locking device comprising locking means adapted to oppose movements of the movable element in the receiver assemblage, means normally exerting force upon said locking means for the operation thereof, means of greater force opposing the force of said first named means acting upon said locking means, and means whereby force from the fluid pressure in the system opposes the force of said last named means normally preventing any action on its part but that force is normally exerted upon'said locking v member for the operation thereof in clamping said rod but that an increase or decrease in fluid pressure from the normal fluid pressure acting upon said diaphragms will cause a lessening of force exerted upon said locking members.

adapted to allow such action and consequent overcoming of the force from said first named means upon a predetermined decrease in fluid pressure from the normal fluid pressure in the system.

3. In a hydraulic remote control system having a receiver assemblage with a movable element, a locking device comprising a rod connected to the movable element in the receiver assemblage, two locking members disposed to ex-,

ert clamping action upon said rod, stop means for said locking members so that if either of said locking members rests against the stop the clamping action upon said rod will be relieved, spring means whereby force is normally exerted upon one side of one of said locking members, means whereby force from the fluid pressure in the system opposes the force of said spring means, said force from the fluid pressure means being normally less than the force from said spring means, means whereby force from the fluid pressure in the system is normally exerted upon the opposite side of the other of said locking members, spring means whereby force from the spring opposes the force from'' said last named fluid pressure means, the force fromsaid last named spring means being normally less than the force from said last named fluid pressure means, and means whereby under the normal fluid pressure in the system the resultant force of the opposing forces of said flrst named spring means and said first named fluid pressure means is substantially equal to the resultant force of the opposing forces of said last named fluid pressure means and said last named springs means, each of said resultant forces actsure upon said rod.

5. A locking device for hydraulic remote control systems having a receiver assemblage with a movable element, arod connected to the movable element in the receiver assemblage, two locking members adapted to clamp said rod between them against movement, stops for each of said locking members, a compression spring, a flexible diaphragm whereby force from fluid pressure opposes the action of said sprin a'compression spring of less force than said flrst named spring, a flexible diaphragm whereby force from fluid pressure opposes the action of said last named compression spring, a rocking member associated with said last named compression spring and diaphra for the transference of force therefrom, and said parts being so arranged that force is normally exerted upon each of said locking members for the operation thereof in clamping said rod but that an increase or decrease in fluid pressure from the normal fluid pressure acting upon said diaphragms will cause one of said locking members-to move against its stop thus relieving the clamping pres- 6. In a locking mechanism for hydraulic remote control systems the combination of a casing, locking means in the casing including a movable part,

ing upon opposite sides of said locking members in a manner to exert clamping action upon said rod, but so arranged that an increase or decrease from the normal fluid pressure in the system will cause movement of said locking members until one of said locking members rests against said stop means thus relieving the clamping action of said locking members upon said rod. 7

4. A locking device for hydraulic remote control systems having a receiverissemblage with a movable element, a rod connected to the movable element in the receiver assemblage, a pivoted lockin: member adapted to clam said rod against movement, a compression spring, a flexible diaphragm whereby force from fluid pressure op oses the action of said spring, a compression spring of and fluid pressure actuated means for controlling the locking action of said movable part comprising pressure actuated diaphragms, and fluid pressure countering springs urging said diaphragms in a direction counter to fluid pressure, said diaphragms being of unequal fluid pressure exposed area and one of said springs having a greater force acting counter to fluid pressure than the other spring.

'7. In a hydraulic remote control system, the combination of a transmitter cylinder, a receiver cylinder, a piston in each of said cylinders, a conduit connecting said cylinders, a hydraulic control fluid in said conduit and cylinders between said pistons, means acting upon said transmitter piston to maintain .a substantially constant fluid pressure in excess of atmospheric pressure in said cylinders and conduit, means acting upon said receiver piston to maintain a substantially equal balancing force to said means acting upon said transmitter piston, locking means and means for rendering said locking means normally eflective to controlling the actuation of said locking means by the diiierential action of said diaphragms and said springs.

LEMUEL E. DOUGHERTY. 

